Planetary & Solar-System Phenomena

Planetary Weather

Weather isn't unique to Earth: planets and moons across the Solar System have clouds, winds and storms.

Wherever a world has an atmosphere and an energy source, air moves, and telescopes are now measuring weather on planets around other stars too.

Observe
Clouds, storms and wind patterns on other worlds.
Measure
Cloud motion, temperature and spectra from telescopes and spacecraft.
Model
Atmospheric models adapted from Earth's climate science.
Explain
Any world with an atmosphere and energy can have weather.

What is it?

Weather is what an atmosphere does: winds, clouds, storms, temperature changes and seasons. It needs an atmosphere and an energy source, usually sunlight, sometimes a planet's own internal heat. Earth's weather is driven by sunlight, rotation and water; other worlds use different ingredients.

Space weather is a different thing. It describes how the Sun's particles and magnetic fields disturb the space around a planet, although the two interact, for example when charged particles create aurora in a planet's upper atmosphere.

How does it happen?

Stage 1
Energy heats an atmosphere unevenly
Stage 2
Air begins to move
Stage 3
Rotation shapes winds and storms
Stage 4
Clouds, storms and seasons develop

What do we actually observe?

Earth: Driven by sunlight, the ocean, the water cycle and rotation. Our own weather is the baseline every other world is compared with.
Mars: A thin carbon-dioxide atmosphere with dust storms. Regional storms are common, and occasionally a storm grows to cover the planet; the 2018 global storm ended the Opportunity rover's mission. The thin air means even fast winds push with little force.
Venus: A dense carbon-dioxide atmosphere with sulfuric-acid clouds and a surface pressure about 90 times Earth's. Its upper clouds circle the planet in about four Earth days, much faster than the planet itself rotates.
Jupiter: Bands of clouds and jets. The Great Red Spot is a huge storm that has been observed for at least about 190 years, roughly the size of Earth or somewhat larger, and shrinking.
Saturn: Large storms, called Great White Spots, appear about once per Saturn year (roughly 29 Earth years), and a hexagonal jet stream circles the north pole.
Neptune: Measured winds of over 2,000 km/h, among the fastest in the Solar System, despite little sunlight. Dark storm spots appear and disappear; the reason for the strong winds remains an open question.
Titan: Saturn's moon has clouds, rain and lakes made of methane and ethane rather than water.
Exoplanets: Telescopes have inferred clouds, hazes and winds on hot giant planets. Evidence suggests some ultra-hot worlds have iron vapor on the day side that condenses on the night side.

How do scientists detect it?

Spacecraft. Orbiters and probes such as Cassini, Juno, Mars orbiters and Voyager measure winds, temperatures and cloud composition.
Hubble and JWST. Watch storms on distant planets and study exoplanet atmospheres by splitting starlight that passes through them.
Ground-based telescopes. Amateur and professional observers track storms on Jupiter and Saturn.

How we know

Storms are tracked by following cloud features from image to image, and winds on distant worlds are inferred from shifts in spectral lines or from temperature differences between the day and night sides.

Why does it matter?

Other planets are natural experiments for understanding climate physics.
Studying atmospheres helps us judge which worlds might be habitable.

The SpaceWeatherTracker connection

Aurora on Earth, Jupiter and Saturn shows how the Sun's particles interact with a planet's atmosphere and magnetic field. SpaceWeatherTracker tracks that side of the story for Earth every day.

Primary family: Planetary & Solar-System Phenomena